Brake



Sept. 12, 1933.

BRAKE Filed Dec. 2, 1929 W. H., DELAHAYE INVENTOQ WALTER H. DELAHAYE.

BY ATTOR N EY Patented Sept. 12, 1933 UNITED STATES I wa BRAKE Walter H. Delahaye, Ottawa, Ontario, Canada, assignor to Bendix Brake Company, South Bend, Ind;

Application December 2, 1929. Serial No. 110,937

' 7 Claims. (01. 188--78) This invention relates to automobile brakesand has for its object to provide a novel brake having-a servo action developed by a shoe which is either directly connected to one of the main shoes or is integral therewith.

A novel feature of the device also resides in the brake-applying means which provides a simple and effective means for transmitting a servo initiated force to the main shoe.

The invention consists in the combination, construction and arrangement of parts hereinafter described and more particularly pointed out in the appended claims.

A number of embodiments of the invention are illustrated by way of example, in the accompanying drawing in which:

Figure 1 is an elevation partially in section on line 1-1 of Figure 2 of a, portion of one form of the invention showing applying means which may conveniently be used with all modi fications of the servo shoe disclosed herein.

Figure 2 is a detail of the applying means shown in Figure 1.

Figures 3 and 4 show modifications in the construction of the resilient connection between one of the main shoes and the servo shoe attached thereto.

Figure 5 and 6 show details of the spring support used in the construction shown in Figure 4.

,1 indicates a brake drum in which a pair of shoes 2 and 3 are mounted in the usual manner on a fixed pivot 4. The free end of the brake shoe 2 is provided with a flat surface 5 considerably greater in area than is usually employed in ordinary cam brakes. This surface is intended to co-operate with the applying means carried on the other shoe 3. These means are carried on and operated by a rockshaft 6 pivoted in the free end of the shoe 3. This shaft 6 carries a 40 cam 7, which is fixed thereto in the customary manner and also a depending lever 8. The free end of the shoe 3 may be formed with a pair of spaced ears 9, which may be constructed by separating the two parts of the rib of the shoe, the shoe being formed by a pair of angles placed back to back. Between these cars may be fitted constructed to act as a servo shoe and therefore must have a limited freedom of movement in a circumferential direction. In Figure 1 this is provided for by constructing a resilient loop 13 v in the shoe. The web of the shoe is out 01f and the remaining fiat flange portions are formed into the loop 13 to which a certain amountof resiliency must be imparted.v If the nature of the material from which the shoe is made permits tempering this may be done. Another expedient in the shape of a spring insert 14 may I be resorted to. i

In the modification shown in Figure 3, the servo section is separate from the main part of the shoe 3. The'central webs of the portion 12 are separated to provide spaced parallel parts 15 and the adjacent portions 16 of the web of the. shoe 3 are similarly spread and are adapted to receive the parts 15 between them. Any means may be used to hold these parts in sliding assembled relation. This detail has not been shown in the drawing as any well-known construction may be employed. The parts when so assembled form a pocket to receive a compression spring 1'7 which acts to keep the parts in extended position.

In the construction shown in Figure 4, the webs of the shoe 3 and the servo portion 12 are only separated sufficiently to permit their being overlapped in superimposed relation and in such a position that the large openings 18 provided therein are normally in register. In the open. ings a spring 19 is mounted by means of spring seats 20 which have a slotted end 21 to receive the material of the webs to center the seats and hold the spring in its operative position.

The operation of the brake, through apparent from the above description, will be briefly reviewed. When the shaft 6 is turned in the operation of applying the shoes by means of the usual lever 22 and brake rod 23, the shoes are expanded and engage the drum 1 throughout their length. If the drum is rotating in a clockwise direction the servo portion 12 will be urged in a like direction and can do so by the resilient mounting which connects it to the remainder of the. shoe, 3. This movement will carry the shaft 6 with it, clearance 24 being provided in the opening in the axle flange to permit this. As the shaft moves it carries the lever 8 against the stop. 11 and therefore the free end of this lever moves in the opposite direction and exerts an expanding force on the surface 5 of the shoe 2.

Various modifications of the above constructions may be made and it is the intention to cover all such modifications as may rightly fall within the scope of the appended claims.

What I claim is:

1. In a servo brake, a pair of pivoted shoes, one shoe having a main portion and a servo portion, said portions being resiliently connected, said portions having a web composed of two individual webs lying back to back, said individual Websbeing spaced .at theadjacentends of the portions to present pveflapping faces adapted to slide on one another, a spring opening formed in the separated overlappingsections of the web, and a spring in said opening.

2. In a servo brake, a pair of pivoted shoes, one of said shoes having a servo section resiliently attached thereto at itsfree end, a cam shaft mounted in the free end of lthe..servo .shoe, a cam fixed on said shaft and alever free on the shaft, a stop adapted to be engaged by the lever and a surface on the-free end of thewthm pivoted shoe to be engaged by thefree endwof the lever.

3.-In a servo-brake as @set forth :in '-.claim' 2, rsai'd-stoplbeingpositioned:between theicam' shaft =1 and lthe point' f engagement of -thelever and withe engagingaweb portion.

the :free end-10f -.the other shoe; and 'in 'advance nobthe lever in regardmto -the: direction -of="r,ota 7 -tion in -which-the desired servo action-is to --take iplace.

In va-seiwo brakeasset :forth in -:claim 2, said servo shoe having spaced ears in which the camshaft is journalled, said lever having perforated bifurcations loosely journalled on the shaft, said cam being fixed to said shaft and located between the bifurcated ends of the lever.

5. In a brake shoe, a main section adapted to be mounted on a fixed pivot and a servo section resiliently connected thereto, .both of said sec- =*tions being adapted to sengage the 'same zone of the surface of a cooperating brake drum, said "connection presenting slidably engaging parts on I the respective sections and resilient means to maintain the sections in an extended position.

6. In a brake shoe a main section adapted to be mountedon afixed pivot and a servo section .resilie'n'tly connectedthereto, both of said sections being adaptedtmengage the same zone of the surface of a cooperating brake drum, said sec- -tions*bingwachformed with a flange carrying airiction facing and a reinforcing Web, said websbeing provided at their adjacent ends with -separated portions :slidably engaging the r correspcndingmor-tionswfethe .web of the othersecw-tion in combination "with wspringseated-between 7. A brake shoereomprising az-member formed win-two -parts includinga ifiange bent-@to :provide 'airfiexible connection Y-betwcen the -.-parts.

WALTER :H. DELAHAYE. 

